Turbines are widely used in a variety of aviation, industrial, and power generation applications to perform work. Each turbine generally includes alternating stages of circumferentially mounted stationary vanes and rotating blades. Each stationary vane and rotating blade may include an airfoil connected to a platform. A compressed working fluid, such as steam, combustion gases, or air, flows along a gas path across the stationary vanes and rotating blades in the turbine. The stationary vanes accelerate and direct the compressed working fluid onto the subsequent stage of rotating blades to impart motion to the rotating blades and perform work.
Increased temperatures of the compressed working fluid generally improve the performance, efficiency, and/or output of the turbine. However, the increased temperatures may also lead to increased erosion, creep, and/or low cycle fatigue to the airfoils and platforms of the stationary vanes and rotating blades. A cooling media released through the airfoils and/or platforms may provide film cooling across these surfaces, and trenches in the airfoils and/or platforms may enhance even distribution of the cooling media across these surfaces. However, erosion or other damage to the trenches may lead to streaming of the cooling media across the airfoils and/or platforms, resulting in uneven cooling of the airfoils and/or platforms. Therefore, an improved airfoil and method for cooling an airfoil platform that varies the distribution of the cooling media across the external surfaces of the airfoils and/or platforms would be useful.